The Data-Over-Cable Service Interface Specification (DOCSIS) was established by cable television network operators to facilitate transporting data traffic, primarily Internet traffic, over existing community antenna television (CATV) networks. In addition to transporting data traffic, as well as television content signals over a CATV network, multiple services operators (MSO) also use their CATV network infrastructure for carrying voice, video on demand (VoD) and video conferencing traffic signals, among other types.
The advent of DOCSIS 3.0 has facilitated the provision of better service to subscribers. However, because MSOs typically do not immediately upgrade their networks due to cost, the DOCSIS 3.0 equipment is backwards compatible with DOCSIS 2.0 and DOCSIS 1.X. Thus, the hybrid fiber coax (HFC) network typically includes both legacy DOCSIS channels and DOCSIS 3.0 channels. While subscribers would typically prefer their DOCSIS 3.0 equipment to connect to DOCSIS 3.0 channels, often these devices are connecting on legacy channels. The typical solution is for a cable modem termination system (CMTS) to move the DOCSIS 3.0 devices to DOCSIS 3.0 channels.
Like reference numbers and designations in the various drawings indicate like elements.